400 with 440 crank

Even if you have the 440 crank on hand it might cost you more to build the engine than if you buy a new stroker crank. Check your local area to see if there is anyone who has the ability to turn the mains and counterweights for you. Other problem with a factory 440 crank is that you have the big Mopar rod journals. That means you are stuck with heavy Mopar type rods and big bearings and maybe the big heavy piston pin.

There are lots of ways to build a stroker big block these days. Using a factory 440 crank is not necessarily the best way anymore although it works just fine if you have the right shop nearby who can do the heavy work for you.
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This was my thinking when I built mine. And the only thing that is used is the block it self. A total bolt in, no grinding or clearancing, other than flashing clean up. Lite recip. weight, pistons not too short or too long and heavy, a lot of grunt for street n strip. I`ll always go bigger. Not arguing, jmo. --I don`t even think we`ve got a good crank man around here anymore either.